Cons: Sometimes slightly sibilant, HD650 has more detail and speed with no sibilance at all (imo)

More than adequate sound considering the price I got them for (~$300). Clearer sound then the HD650, sounds like the DT has slightly deeper bass also. But I cannot help but feel like the HD650 are slightly faster in mids and highs and therefore have also more detail in these areas, even though the DT has more treble. Sometimes the treble sounds like it is too pronounced, but it is more than tolerable, often rather enjoyable. I prefer the HD650, but often listen to the DT880 to enjoy the enhanced sound clarity (more treble, less lower midrange/higher bass compared to the HD650). I like them. The sound just "makes sense".